Navigation Disappears When I Activate WP Easy Recipe

I had this issue too. The problem comes in play here: https://plugins.trac.www.ads-software.com/browser/wp-easy-recipe/trunk/lib/class-wp-easy-recipe.php#L253

First, you aren’t sharing the post category with the CPT so you can remove the is_category() check since you don’t need to include the CPT in those archives and only on the shared post tag archive. Also, you should be doing a check prior to this to be sure you are only modifying the proper query. This is modifying every query run on that page, including the menu query. There should be a check to ensure it is only modifying the correct query.